Electronic device starter and vehicle tire monitoring system

ABSTRACT

To provide an electronic device starter that does not waste electric power while it is not being used and a vehicle tire monitoring system in which the starter is used for eliminating waste of electric power of batteries for its detectors. In a vehicle tire monitoring system according to the present invention, a monitor unit sends a start signal at time intervals T 1  by using an electromagnetic wave, a rectifier circuit  33  in a detector  3  which received the start signal converts a high-frequency electromotive force caused by the start signal at an antenna  31  into electric energy, this electric energy operates a central processing section  34,  a detector section  35,  and a transmitting section  36,  the central processing section  34  which started operating places an FET  382  in the on state to supply electric power from a battery  381  to a sensor section  37  to operate the sensor section  37.

TECHNICAL FIELD

The present invention relates to an electronic device starter forstarting operation of electronic devices by remote control and to avehicle tire monitoring system in which the starter is used to reducebattery drain.

BACKGROUND ART

Remote controllers have been known that operate any electronic devices,including electric appliances such as television sets, audio devices,and lighting apparatuses, by remote control. A remote controller of thistype consists of a palm-sized operation module contained in a smallcasing and a controller provided within an electronic device to becontrolled and operated. The controller is consistently supplied withelectric power so as to be kept ready for receiving a control signalsfrom the operation module.

Tire monitoring systems have also been known in which a sensor isprovided for each tire and the conditions of the tire that are detectedby the sensor are wirelessly transmitted over a communication circuit toa monitor provided in the vicinity of the driver's seat of a vehicle anddisplayed for ready monitoring of the conditions of tires of the vehicleat the driver's seat.

Most tire monitoring systems of this type use a battery (a storagebattery or dry cell) as a power supply for the sensor because the sensorcircuit provided in their sensor unit consumes more electric power thantheir communication circuit. If a sensor that operates on a battery isused, the battery must be replaced, or recharged if the battery is asecondary battery, before it becomes exhausted because batteryexhaustion would stop the operation of the sensor. If a battery isexhausted frequently, it takes a lot of trouble to replace or rechargethe battery, therefore measures are taken for minimizing battery drain.

For example, in a sensor disclosed in Japanese Patent Laid-Open No.3-154999, means is provided that supplies power to a receiving moduleonly for a predetermined time period at predetermined time intervals tooperate it and supplies power to a sending module only duringtransmission in order to minimize battery drain.

In a sensor disclosed in Japanese Patent Laid-Open No. 2-268027, timingfor receiving an interrogation signal and sending a reply signal iscontrolled by a timer circuit and power supply to other circuits exceptthe timer circuit is shut off unless the interrogation signal is to bereceived or the reply signal is required to be sent so that batterydrain is minimized.

However, the conventional remote controllers described above are not inkeeping with energy saving commonly demanded today because a controllingunit provided within an electronic device is constantly supplied withpower and thus a large amount of electric power is unnecessarilyconsumed.

The tire monitoring systems described above also waste battery power intheir sensors during a time period in which monitoring of the conditionsof tires is not required, that is, the vehicles are not used.

In light of the problems described above, an object of the presentinvention is to provide an electronic device starter that does not wasteelectric power while the device is not being used and a vehicle tiremonitoring system in which the electronic device starter is used toeliminate unnecessary battery power consumption in its sensors.

SUMMARY OF THE INVENTION

To achieve the object, the present invention configures an electronicdevice starter for wirelessly starting operation of an electronic devicefrom a position remote from the electronic device, with an operationdirecting unit to be operated by a user and an operation control unitprovided in the electronic device so that the operation control unitoperates on energy of a wireless signal, such as anelectromagnetic-wave, ultrasonic, or optical signal, that is receivedfrom the operation directing unit. This avoids electric powerconsumption in the electronic device and operation control unit during aperiod in which the electronic device is not in operation.

The operation directing unit in the electronic device starter of thepresent invention includes start signal sending means for wirelesslysending a start signal that directs the electronic device to startoperation, for example. The operation control unit further comprisesreceiving means for receiving a wireless signal sent from the operationdirecting unit; detection means for detecting a start signal from amongthe wireless signals received by the receiving means; energy conversionmeans for converting the wireless signal received by the receiving meansinto electric energy for operating the operation control unit; switchmeans interposed on a power supply line supplying operating power to theelectronic device for turning on and off power supply to the electronicdevice; and switch control means for changing the switch means from theon state to the off state when the detection means detects the startsignal.

When a start signal is wirelessly sent from the start signal sendingmeans of the operation directing unit remote from the electronic deviceto the operation control unit in the electronic device starter havingthe configuration described above, the wireless signal is received bythe receiving means of the operation control unit and the receivedwireless signal is converted by the energy conversion means into anelectric signal for operating the operation control unit. The electricsignal causes the operation control unit to start operating, then astart signal is detected from among wireless signals by the detectionmeans, and then the switch control means changes the status of theswitch means from the off state to the on state.

The switch means is interposed on the power supply line supplyingoperating power to the electronic device. Therefore, if the switch meansis in the off state, operating power supply to the electronic device isshut off and the electronic device is placed in the non-operation state.

When the switch means is changed from the off state to the on state,operating power is supplied to the electronic device and the electronicdevice starts operation.

Thus, the operation control unit operates on the energy of the wirelesssignal received and therefore power consumption in the electronic deviceand the operation control unit can be avoided while the electronicdevice is not in operation.

Furthermore, according to the present invention, the start signal issent from the operation directing unit for a predetermined time periodfrom operation start time to operation stop time of the operationdirecting unit and the switch control means of the operation controlunit places the switch means in the on state only while electric energyis being supplied from the energy conversion means so that the operationcontrol unit operates only while the energy triggered by the startsignal is being supplied to it. The time intervals at which a startsignal is sent are set shorter than a time period in which energyconversion means can supply by reception of one start signal an amountof electric energy large enough for the operation control unit tooperate for a predetermined period of time. Accordingly, the operationcontrol unit can continually operate during a time period from operationstart time to operation stop time of the operation directing unit when astart signal is sent from the operation directing unit at theabove-mentioned time intervals.

In addition, the present invention provides state retaining means in theoperation control unit for keeping the switch means in the on state ifelectric energy supply from the energy conversion means stops after theswitch control means changes the switch means from the off state to theon state. This can keep the switch means in the on state after electricenergy supply from the energy conversion means in the operation controlunit stops. Accordingly, operating power is supplied to the electronicdevice over the power supply line even if the operation control unit isshut down, thereby allowing the electronic device to be kept inoperation.

Furthermore, switch state detection means is provided in the operationcontrol unit for detecting the on/off state of the switch means andmeans is provided in the switch control means for placing the switchmeans in the off state based on the result of detection by the switchstate detection means if the switch means is in the on state and thedetection means detects a start signal. In this arrangement, when theoperation control unit receives a start signal sent from the operationdirecting unit while the electronic device is in operation, the switchstate detection means detects the on/off state of the switch means and,if the switch means is in the on state, places the switch means in theoff state, therefore the electronic device is kept in operation during aperiod from time at which the start signal is received in the operationcontrol unit until the next start signal is received.

In addition, an operation section including a switch is provided in theoperation directing unit so that the start signal sending means sends astart signal according to an actuation of the switch by an operator.Thus, the start signal can be sent from the start signal sending meanswhen the switch on the operation section is operated by the operator.

According to the present invention, identification information foridentifying an electronic device to be operated is included in a signalsent from the operation directing unit to the operation control unit sothat the operation control unit turns on or off the electronic device ifits own identification information matches identification information itreceives.

According to the present invention, pulses of electromagnetic waves,sound waves, ultrasonic waves, or light in ambient atmosphere of theelectronic device are converted into electric energy and the electricenergy is used as a portion of energy for operating the operationcontrol unit.

According to the present invention, the above-described electronicdevice starter is applied to a vehicle tire monitoring system.

In the tire monitoring system of the present invention, a detector isprovided at each tire that includes a sensor unit operating on electricpower supplied from a battery and communication means for wirelesslysending tire conditions detected by the sensor unit as detectioninformation. The monitoring system also comprises a monitor unitinstalled in the vicinity of the driver's seat of the vehicle forreceiving and displaying the detection information sent from thedetector.

The monitor unit in the tire monitoring system of the present inventionfurther comprises start signal sending means for wirelessly sending astart signal that directs the detector to start operating and thedetector comprises operation control means.

This operation control means comprises receiving means for receiving astart signal sent from the monitor unit, detection means for detectingthe start signal from among signals received by the receiving means,energy conversion means for converting a signal received by thereceiving means into electric energy for operating the operation controlmeans, switch means interposed on a power supply line supplyingoperating power from a battery to the sensor unit for turning on and offelectric power supply to the sensor unit, and switch control means forchanging the switch means from the off state to the on state when thedetection means detects the start signal.

In the vehicle tire monitoring system of the present invention, when astart signal is wirelessly sent by the start signal sending means of themonitor unit, the receiving means of the operation control means in thedetector receives the wireless signal and the received wireless signalis converted by the energy conversion means into an electric signal foroperating the operation control means. This electric signal causes theoperation control means to start operating and, when the start signal isdetected from among wireless signals by the detection means, the offstate of the switch means is changed to the on state by the switchcontrol means and operating power is supplied from the battery to thesensor unit to operate the sensor unit. When the switch means, which isinterposed between the battery and the sensor unit, is in the off state,operating power to the sensor unit is shut off and therefore the sensorunit is placed in the non-operation state. When the switch means ischanged from the off state to the on state, operating power is suppliedto the sensor unit and the sensor unit starts operating. Because theoperation control means operates on energy of the wireless signalreceived, no electric power is consumed in the sensor unit and operationcontrol means while the sensor unit is in a non-operation state, thusavoiding unnecessary battery wastage.

According to the present invention, time intervals at which the startsignal is sent are set shorter than a time period in which electricenergy can be supplied by reception of one start signal. Thus, if astart signal is sent from the monitor unit at the time intervals, theoperation control means of the detector continuously operates in a timeperiod from a time at which the monitor unit starts to operate until itstops. Therefore, the total amount of time that the start signal is sentfrom the monitor unit can be reduced.

According to the present invention, when a start signal is received bythe receiving means of the detector, the detector performs a detectioninformation transmission process and sends the detection information tothe monitor unit.

According to the present invention, the communication means of thedetector operates on electric energy outputted from the energyconversion means. Thus, the communication means does not consumeelectric power of the battery, and accordingly, battery powerconsumption can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram showing an entire vehicle tiremonitoring system according to a first embodiment of the presentinvention;

FIG. 2 is a block diagram showing an electric system circuitry of adetector according to the first embodiment of the present invention;

FIG. 3 is a block diagram showing an electric system circuitry of amonitor unit according to the first embodiment of the present invention;

FIG. 4 is a diagram showing a display panel of the monitor unitaccording to the first embodiment of the present invention;

FIG. 5 is a diagram showing transmission timing of a start signal and areply signal according to the first embodiment of the present invention;

FIG. 6 is a diagram showing transmission timing of the start signal andreply signal according to the first embodiment of the present invention;

FIG. 7 is a diagram for explaining the header part of the start signalaccording to the first embodiment of the present invention;

FIG. 8 is a diagram for explaining an information part of the startsignal according to the first embodiment of the present invention;

FIG. 9 is a flowchart for explaining an operation of the monitor unitaccording to the first embodiment of the present invention;

FIG. 10 is a flowchart for explaining an operation of the detectoraccording to the first embodiment of the present invention;

FIG. 11 is a diagram showing transmission timing of a start signal and areply signal according to a second embodiment of the present invention;

FIG. 12 is a flowchart for explaining an operation of a monitor unitaccording to the second embodiment of the present invention;

FIG. 13 is a flowchart for explaining an operation of a detectoraccording to the second embodiment of the present invention;

FIG. 14 is a block diagram of an electric system circuitry of a detectoraccording to a third embodiment of the present invention;

FIG. 15 is a block diagram showing an electronic device including anelectronic device starter according to a fourth embodiment of thepresent invention;

FIG. 16 is a block diagram showing an electric system circuitry of anoperation directing unit according to the fourth embodiment of thepresent invention;

FIG. 17 is a block diagram showing an electric system circuitry of anoperation control unit according to the fourth embodiment of the presentinvention;

FIG. 18 is a flowchart for explaining an operation of the operationdirecting unit according to the fourth embodiment of the presentinvention;

FIG. 19 is a flowchart for explaining an operation of the operationcontrol unit according to the fourth embodiment of the presentinvention;

FIG. 20 is a block diagram showing an electric system circuitry of theoperation control unit in which a manual switch is provided according tothe fourth embodiment of the present invention;

FIG. 21 is a block diagram of an electric system circuitry of anoperation directing unit according to a fifth embodiment of the presentinvention;

FIG. 22 is a block diagram of an electric system circuitry of anoperation control unit according to the fifth embodiment of the presentinvention;

FIG. 23 is a flowchart for explaining an operation of the operationdirecting unit according to the fifth embodiment of the presentinvention;

FIG. 24 is a flowchart for explaining an operation of the operationcontrol unit according to the fifth embodiment of the present invention;

FIG. 25 is a block diagram of an electric system circuitry of anoperation directing unit according to a sixth embodiment of the presentinvention;

FIG. 26 is a block diagram of an electric system circuitry of anoperation control unit according to the sixth embodiment of the presentinvention;

FIG. 27 is a block diagram of an electric system circuitry of anoperation directing unit according to a seventh embodiment of thepresent invention; and

FIG. 28 is a block diagram of an electric system circuitry of anoperation control unit according to the seventh embodiment of thepresent invention.

DETAILED DESCRIPTION

One embodiment of the present invention will be described below withrespect to the drawings.

FIG. 1 is a configuration diagram showing an entire vehicle tiremonitoring system according to a first embodiment of the presentinvention, FIG. 2 is a block diagram showing electric system circuitryof a detector according to the first embodiment, and FIG. 3 is a blockdiagram showing electric system circuitry of a monitor unit according tothe first embodiment.

In FIG. 1, reference numeral 1 indicates a vehicle, which may be afour-wheel passenger car, for example, in which a detector 3 is providedat each of the four tires 2 for detecting the conditions of the tire. Inaddition, a monitor unit 4 is installed in the vicinity of the driver'ssheet of the vehicle 1. Antennas 5 connected to the monitor unit 4 areprovided in the vicinity of the front wheels and in the vicinity of therear wheels.

The detector 3 comprises an antenna 31, an antenna selector switch 32, arectifier circuit 33, a central processing section 34, a detectorsection 35, a transmitting section 36, a sensor section 37, and a powersupply section 38 as shown in FIG. 2.

The antenna 31, which is used for communicating with the monitor unit 4via an electromagnetic wave, is tuned to a predetermined communicationfrequency, which may be 415 MHz, for example.

The antenna selector switch 32 is formed by an electronic switch, forexample, and switches the antenna 31 between the connection of theantenna 31 with the rectifier circuit 33 and the detector section 35 andthe connection of the antenna 31 with the transmitting section 36, underthe control of the central processing section 34.

The rectifier circuit 33 is formed by a well-known full-wave rectifiercircuit comprising diodes 331 and 332, a capacitor 333, and a resister334. The antenna 31 is connected to the input of the rectifier circuit33 through the antenna selector switch 32. The rectifier circuit 33rectifies a high-frequency current induced at the antenna 31 into directcurrent. The direct current outputted from the rectifier circuit 33 isprovided to the central processing section 34, detector section 35, andtransmitting section 36 as an operating current.

The central processing section 34 comprises a well-known CPU 341, adigital/analog (hereinafter referred to as D/A) converter circuit 342and a memory section 343. The CPU 341 operates based on a program storedin a semiconductor memory in the memory section 343. When the CPU 341 issupplied with power and starts to operate, it connects a battery 381 inthe power supply section 38 to the sensor section 37 to operate it andwirelessly sends data detected by the sensor section 37 to the monitorunit 4. If a signal received from the monitor unit 4 contains a writeinstruction along with information to be written, the CPU 341 updates,adds or deletes information in the memory section 341 according to thewrite instruction.

In the program for the CPU 341, specification is set that the CPU 341should send a reply signal when it receives a start signal from themonitor unit 4. Also specified in the program for the CPU 341 is theminimum time interval between transmission of a reply signal to themonitor unit 4 and the next reply signal transmission, as a reply signaltransmission time interval T2. In the present embodiment, the startsignal is set in the program as a signal for requesting a reply signalfrom the detector 3.

The memory section 343 comprises a ROM in which the program foroperating the CPU 341 is recorded and an electrically rewritablenon-volatile semiconductor memory such as an EEPROM (electricallyerasable programmable read-only memory). In addition, identificationinformation unique to each detector 3 is pre-stored during manufacturingin an area in the memory section 343 that is specified as beingunrewritable.

The detector section 35 comprises a diode 351 and an analog/digital(hereinafter referred to as A/D) converter 352. The anode of the diode351 is connected to the antenna 31 and its cathode is connected to theCPU 341 in the central processing section 34 through the A/D converter352. This allows a received signal to be converted into digital data bythe detector section 35 and inputted into the CPU 341.

The transmitting section 36 comprises an oscillator circuit 361, amodulator circuit 362, and a high-frequency amplifier circuit 363. Inthe transmitting section 36, a carrier is oscillated by the oscillatorcircuit 361, the oscillated carrier is modulated by the modulatorcircuit 362 based on an information signal inputted from the centralprocessing section 34 and then provided to the antenna 31 through thehigh-frequency amplifier circuit 363 and the antenna selector switch 32.

The sensor section 37 comprises a first and second sensors 371 and 372,a selector switch 373, and an A/D converter circuit 374. As the firstand second sensors 371 and 372, sensors are used that detect thecondition of the tires 2, convert them into electric signals, and outputthem. For example, sensors such as air pressure sensors, temperaturesensors, pressure sensors, humidity sensors, and vibration sensors maybe used. In the present embodiment, an air pressure sensor is used asthe first sensor 371 that detects the air pressure in a tire and outputsa voltage corresponding to the detected air pressure and a temperaturesensor is used as the second sensor 372 that detects the temperature inthe tire and outputs a voltage corresponding to the temperature.

The selector switch 373 is formed by an electronic switch, for example,and selects and connects the output of the first sensor 371 or theoutput of the second sensor 372 to the input of the A/D convertercircuit 374 under the control of the central processing section 34.

The A/D converter circuit 374 converts an output voltage inputted fromthe first sensor 371 or the second sensor 372 into a digital value andoutputs it to the CPU 341.

The power supply section 38 comprises a battery 381 and an N-channelfield-effect transistor (hereinafter referred to as an FET) 382. Thepositive pole of the battery 381 is connected to the drain of the FET382 and electric power outputted from the source is supplied to thesensor section 37. A control signal outputted from the CPU 341 isinputted into the gate of the FET 382 and the FET 382 performs switchingoperation according to the control signal. The control signal inputtedinto the gate of the FET 382 is an active HIGH signal. The FET 382 isturned off when the control signal inputted into the gate goes LOW andpower supply from the battery 381 to the sensor section 37 is shut off.The CPU 341 outputs a low-level control signal to the gate of the FET382 when operating power is not supplied.

The monitor unit 4 comprises an antenna 5, a selector switch 41, areceiving section 42, a sending section 43, a central processing section44, and a display section 45 as shown in FIG. 3. The monitor unit 4 issupplied with operating power from a battery 6 of the vehicle 1 throughan ignition key 7.

The antenna 5 is used for communicating with the four detectors 3 byusing an electromagnetic wave and is tuned to a predeterminedcommunication frequency, which may be 415 MHz, for example.

The antenna selector switch 41 is formed by an electronic switch, forexample, and switches the antenna 5 between the connection of theantenna 5 with the receiving section 42 and the connection of theantenna 5 with the sending section 43 under the control of the centralprocessing section 44.

The receiving section 42 comprises a receiver 421 and an A/D convertercircuit 422. The receiver 421 of which the input is connected to theantenna 5 through the antenna selector switch 41 receives a reply signalsent from the detector 3, detects it, and outputs the signal to thecentral processing section 44 through the A/D converter circuit 422.

The sending section 43 comprises a transmitter 431 and a D/A convertercircuit 432. The transmitter 431 converts a start signal which isinputted from the central processing section 44 and to be provided tothe detector 3 into a high-frequency signal and provides it to theantenna 5 through the antenna selector switch 41.

The central processing section 44 comprises a well-known CPU 441 andmemory 442 and, when operating power is supplied from the battery 6 tothe monitor unit 4, automatically sends a start signal and displayssensor information received from each of the four detectors 3 associatedwith each of the four tiers 2, on a display panel in a display section45, as will be described later. The start signal is repeatedly sent atstart signal sending time intervals T1 preset in a program for the CPU441.

Display section 45 displays information detected by the sensor in eachdetector 3 and inputted from the CPU 441. The display section 45includes the display panel 450 as shown in FIG. 4. A diagram of thevehicle is drawn in the center of the upper section of the display panel450 so that the positions of the tires can be readily seen. Provided onboth sides of the drawing of the vehicle and associated with the tiresare LEDs 451 a–451 d, which switch between two colors, red and green, toindicate whether the air pressure of each of the tires is proper or not,and LEDs 452 a–452 d which switch between two colors, red and green, toindicate whether the temperature in each of the tires is proper or not.In addition, a liquid-crystal display 453 is provided in the lowersection of the display panel 450 for providing the digital display ofthe detected air pressure and temperature of each tire 2.

An operation of the vehicle tire monitoring system having theconfiguration described above will be described below with reference toFIGS. 5 to 10.

A feature of the tire monitoring system according to the presentembodiment is that operating power is supplied from the battery 381 tothe sensor section 37 in each detector 3 only while the monitor unit 4is operating. This can avoid unnecessarily consuming electric power ofthe battery 381 of each detector 3 and provide longer life of thebattery 381 than possible heretofore, therefore it becomes unnecessaryto replace the battery 381 of each detector 3 at frequent intervals.

That is, the FET 382 in power supply section 38 of each detector 3 isplaced in the on state and power is supplied from the battery 381 to thesensor section 37 only while the CPU 341 is operating. This will bedetailed below.

The monitor unit 4 operates only while power is being supplied from thebattery 6 to the monitor unit 4 after the ignition key 7 of the vehicle1 is operated. After starting operation, the monitor unit 4 sends astart signal (SA1) and resets a timer to start timekeeping (SA2) at timeintervals T1, as shown in FIGS. 5, 6, and 9.

The start signal consists of a header part followed by an informationpart. The header part is used for providing electric power to thedetectors 3 and consists of four carrier signals as shown in FIG. 7.After carrier signal is sent for time T31, three carriers areintermittently sent for time T32 at time intervals T32. According to thepresent embodiment, the carrier signals are sent on an intermittentbasis as described above so that the start signal can be distinguishedfrom noise. According to the present embodiment, first carrier signaltime T31 is set to 100 ms so that the detector 3 can start operation bythe first carrier signal. Furthermore, the second and subsequent carriersignal times T32 are set to 50 ms so that the detector 3 can continue tooperate at least for one second.

The start signal information part consists of b1-bit binary dataconsisting of a b11-bit ID part followed by b12-bit word part andb13-bit data part, as shown in FIG. 8. According to the presentembodiment, the ID part consists of 4 bits, word part consists of 4bits, and data part consists of 42 bits. All of the detectors 3 or oneor more particular detectors 3 can be specified by the setting in the IDpart. Setting in the word part can specify the content of an instructionor data. Data associated with the setting in the word part is set in thedata part.

When the start signal is sent from the monitor unit 4, the carriersignal in the header part of the start signal causes a high-frequencyelectromotive force at the antenna 31 in each detector 3 and this energyis rectified and smoothed by the rectifier circuit 33 into electricenergy, which is stored in the capacitor 333. This causes electric powerto be supplied to the central processing section 34, detector section35, and the transmitting section 36 in the detector 3 to cause theseelectronic circuits to start operation.

The CPU 341 in the detector 3, which started to operate, recognizes thatthe start signal is received (SB1), then places the FET 382 in the onstate (SB2) to start supplying power from the battery 381 to the sensorsection 37. In addition, it controls and switches the selector switch373 to obtain detection data detected by the first and second sensors371 and 372 (SB3).

Then, the CPU 341 sends a reply signal including the obtained detectiondata to the monitor unit 4 (SB4). The format of the reply signal is thesame as that of the information part of the above-described startsignal. Its own identification data is set in the ID part of the replysignal. The word part indicates that it is a reply signal and the datapart contains data on an air pressure detected by the first sensor 371and data on a temperature detected by the second sensor 372. Accordingto the present embodiment, time required for the detector 3 to send the50-bit reply signal and the time required for the monitor unit 4 to sendthe information part of the start signal are both set to 30 ms.

After sending the start signal, the monitor unit 4 monitors whether ithas received a reply signal from the detector 3 (SA3). When it hasreceived the reply signal, it extracts an identification code from thereply signal it received (SA4) and also extracts data on detected airpressure and temperature (SA5). Then, the monitor unit 4 sends anacknowledge signal to the detector 3 from which the reply signal hasbeen received (SA6). The acknowledge signal is the same as theinformation part of the above-described start signal. Identificationinformation of the detector 3 is set in its ID part. In its word part,information indicating that the signal is an acknowledge signal is set.Nothing is set in its data part.

The monitor unit 4 then displays the detection results it received, onthe display panel 450 (SA7). At this time point, the monitor unit 4compares the detected air pressure and temperature with theirthresholds, which are preset. If it determines that there are anyabnormalities, it causes the LEDs 451 a–451 d and 452 a–452 d to emitred light. On the other hand, if it determines that there are noabnormalities, it causes the LEDs 451 a–451 d and 452 a–452 d to emitgreen light.

Then, the monitor unit 4 determines whether or not time t1 measured byits timer has reached a start signal sending time intervals T1 preset ina program (SA8). If the result of the determination is that the time t1measured by the timer has not reached the start signal sending timeintervals T1, the monitor unit proceeds to the above-described step SA3.If it has reached the start signal sending time intervals T1, itproceeds to step SA1. According to the present embodiment, the startsignal sending time intervals T1 are set to 1 second.

The detector 3 that has sent the reply signal monitors whether or not ithas received an acknowledge signal from the monitor unit 4 (SB5). If ithas received the acknowledge signal, it resets its timer to startmeasuring time. Then, the detector 3 determines whether or not time t2measured by the timer has reached reply signal sending time intervals T2(SB7). If it has reached the reply signal sending time intervals, themonitor unit 4 proceeds to the above described step SB1. According tothe present embodiment, the reply signal sending time intervals T2 isset to 10 seconds. This causes the detector 3 to send the reply signalat intervals T2 (10 seconds).

As described above, the detector 3 can operate for more than 1 second onelectric power obtained by receiving one start signal from the monitorunit 4. Accordingly, the detector 3 keeps operating while the monitorunit 4 is operating and, approximately one second after the monitor unit4 stops operating, the FET 382 of the detector 3 is turned off to stopthe power supply from the battery 381 to the sensor section 37.

Thus, when the vehicle 1 is not in use, that is, the ignition key 7 isin the off state and no electric power is supplied from the battery 6 tothe monitor unit 4, the FET 382 is placed in the off state and thereforeno electric power of the battery 381 in the sensor section 37 isconsumed. This allows the sensor section 37 in the detector 3 to bestarted by remote control from the monitor unit 4 without unnecessarilyconsuming electric power stored in the battery 381.

A second embodiment of the present invention will be described below.

FIG. 11 is a diagram showing transmission timings for a start signal andreply signal in the second embodiment, FIG. 12 is a flowchartillustrating an operation of a monitor unit, and FIG. 13 is a flowchartillustrating an operation of a detector. In these drawings, the samecomponents as those in the first embodiment described above are labeledwith the same reference numerals and the description of which will beomitted.

The second embodiment differs from the first embodiment in that a startsignal is sent from the monitor unit 4 at time intervals T2 and thedetector 3 places an FET 382 in the off state when it receives anacknowledge signal in the second embodiment.

That is, when starting operation, the monitor unit 4 in the secondembodiment sends a start signal (SC1) and resets a timer to cause it tostart measuring time (SC2) as shown in the flowchart in FIG. 12. Then,the monitor unit 4 determines whether or not it has received a replysignal from the detector 3 (SC3). If the result of the determination isthat it has not received the reply signal, it proceeds to step SC8,which will be described later. If it has received the reply signal, thenit extracts and stores an identification code from the received replysignal (SC4), extracts data on detected air pressure and temperature(SC5), and sends an acknowledge signal to the detector 3 from which ithas received the reply signal (SC6). After displaying the receiveddetection result on its display panel 450 (SC7), the monitor unit 4determines whether or not the time t1 measured by the timer has reachedstart signal sending time intervals T1 (SA8). If the result of thedetermination is that the time t1 measured by the timer has not reachedthe start signal sending time intervals T1, the monitor unit 4 proceedsto the above-described step SC3. If time t1 has reached time T1, itproceeds to the above-described step SC1.

When the detector 3 in the second embodiment recognizes reception of astart signal (SD1), it places the FET 382 in a power supply section 38in the on state (SD2) to start power supply from a battery 381 to asensor section 37 and obtains detection data detected by a first sensor371 and a second sensor 372 (SD3).

Then, a CPU 341 of the detector 3 sends a reply signal including theobtained detection data (SD4), and then determines whether or not it hasreceived an acknowledge signal from the monitor unit 4 (SD5) and, if ithas received the acknowledge signal, places the FET 382 in the off state(SD6) and proceeds to the above-described step SD1.

According to the configuration of the second embodiment described above,the detector 3 is operated for approximately one second at timeintervals T2 and in the non-operation state during the remaining time.Accordingly, the FET 382 of the detector 3 can be kept in the off stateand power supply from the battery 381 to the sensor section 37 can bekept stopped during the non-operation state of the detector 3, enablinga longer life of the battery 381 than in the first embodiment.

In the second embodiment, the reply signal may be repeatedly sent atpredetermined time intervals until the detector 3 receives theacknowledge signal. In case the detector 3 cannot obtain the acknowledgesignal in one second or fewer after it receives a start signal, that is,within a time period in which it can operate by means of energy of astart signal, a diode OR circuit is provided in the detector 3 andoperating power is supplied from a rectifier circuit 33 through a firstdiode 391 and from the source of the FET 382 through a second diode 392to a central processing section 34, detector section 35 and atransmitting section 36 as in a third embodiment shown in FIG. 14.

As described above with respect to first through third embodiments byway of example, according to the vehicle tire monitoring system of thepresent invention, energy of a start signal sent from a monitor unit 4causes electric energy to be supplied to operate a CPU 341 in a detector3 and the CPU 341 places an FET 382 in the on state based on the startsignal so that electric power is supplied from a battery 381 to a sensorsection 37 to be operated through the FET 382, therefore, while the FET382 is in the off state and the sensor section 37 is in thenon-operation state, no electric power of the battery 381 is consumed inthe sensor section 37. Thus, operation of the sensor section 37 can bestarted by remote control from the monitor unit 4 without unnecessarilyconsuming electric power.

A fourth embodiment of the present invention will be described below.

FIG. 15 is a block diagram showing an electronic device including anelectronic device starter according to the fourth embodiment, FIG. 16 isa configuration diagram of an electric system circuitry of its operationdirecting unit, and FIG. 17 shows an electric system circuitry of itsoperation control unit. In these drawings, reference numeral 50indicates a remote control unit and reference numeral 60 indicates theelectronic device. The electronic device 60 may be a television, stereo,or an audio device such as a video recorder/player, for example.

The remote control unit 50 consists of a hand-held casing (not shown), awell-known remote control signal sending unit 51 that is contained inthe casing and uses infrared rays, and an operation directing unit 52 ofthe present invention. The audio device 60 comprises a device main unit61 consisting of an electronic device main unit circuit 611 and a remotecontrol signal receiving section 612 and an operation control unit 62 ofthe present invention. Electric power is supplied from a commercialalternating current power source 63 to the device main unit 61 of theaudio device 60 through the operation control unit 62.

The operation directing unit 52 of the remote control unit 50 comprisesan antenna 71, a sending section 72, a central processing section 73,and an operation section 74 as shown in FIG. 16.

The antenna 71, which is used for sending a start signal to theoperation control unit 62 via electromagnetic waves, is tuned to apredetermined communication frequency in the 415 MHz, for example, as inthe first embodiment.

The sending section 72 comprises a transmitter 721 and a D/A convertercircuit 722, converts a start signal inputted from the centralprocessing section 73 into a high-frequency signal, and outputs it tothe antenna 71.

The central processing section 73 comprises a well-known CPU 731 andmemory 732 and sends a start signal when a power operation switch 741 inthe operation section 74 is pressed. The start signal in the presentembodiment is composed only of a header part of the start signaldescribed in the first embodiment.

The operation section 74 includes a momentary power-operation switch741, which is exposed to be operated at the surface of the casing of theunit 50 and presented as a power switch.

The operation control unit 62 comprises an antenna 81, a rectifiercircuit 82, a detector section 83, a central processing section 84, aswitching operation section 85, a switch section 86, a constant powersupply circuit 87, and a voltage detector circuit 88 as shown in FIG.17.

The antenna 81, which is used for receiving a start signal sent from theoperation directing unit 52, is tuned to a predetermined communicationfrequency, which may be 415 MHz, for example.

The rectifier circuit 82 is formed by a well-known full-wave rectifiercircuit comprising diodes 821 and 822, a capacitor 823, and a resistor824. The antenna 81 is connected to the input of the rectifier circuit82. The rectifier circuit 82 rectifies a high-frequency current inducedat the antenna 81 into a direct current and outputs the direct currentas current for operating the detector section 83 and the centralprocessing section 84.

The detector section 83 comprises a diode 831 and an A/D convertercircuit 832. The anode of the diode 831 is connected to the antenna 81and its cathode is connected to the CPU 841 in the central processingsection 84 through the A/D converter circuit 832. Thus, a receivedsignal is converted into digital data by the detector section 83 andinputted into the CPU 841.

The central processing section 84 comprises a well-known CPU 841 and amemory section 842. The CPU 841 operates based on a program stored in asemiconductor memory of the memory section 842. This program causes theCPU 841 to be supplied with power to start operating. If the CPU 841detects a start signal while power is being supplied from a commercialelectric power source 63 to the device main unit 61, turns on/off theswitch section 86 to shut off power from the commercial electric powersource 63 to the device main unit 61. In addition, when the CPU 841detects a start signal while no power from the commercial electric powersource 63 is being supplied to the device main unit 61, the CPU 841turns on/off the switch section 86 so that power is supplied from thecommercial electric power source 63 to the device main unit 61.

The switching operation section 85 comprises N-channel FETs 851 and 852,diodes 853 and 854 and resistors 855 and 856. The drain of the first FET851 is connected to the positive output of the rectifier circuit 82 andits source is connected to the anode of the first diode 853 through theresistor 855. An active-high control signal outputted from the CPU 841is inputted to the gate of the first FET 851. The drain of the secondFET 852 is connected to the cathodes of the first and second diodes 853and 854 and the source is grounded. An active-high control signaloutputted from the CPU 841 is inputted to the gate. The anode of thesecond diode 854 is connected to the positive output of the constantpower supply circuit 87 and the voltage detector circuit 88 through theresistor 856.

The switch section 86 comprises a phototriac 861, a triac 862, a surgeabsorber 863 such as ZNR (registered trademark), and a register 864. Thephototriac 861 comprises an LED 861 a for trigger and a triac 861 bwhich is triggered by light emitted from the LED 861 a. The cathode ofthe LED 861 a of the phototriac 861 is grounded and the anode isconnected to the cathodes of the first and second diodes 853 and 854. Afirst anode of the triac 861 b is connected to the gate of the triac 862and a second anode of the triac 861 b is connected to a second anode ofthe triac 862 through the resistor 864.

A first anode of the triac 862 is connected to one input terminal of theconstant power supply circuit 87 and to one power input terminal of thedevice main unit 61.

One end of the ZNR 863 is connected to the first anode of the triac 862and the other end is connected to the second anode of the triac 862.

One end of the commercial alternating current power source 63 isconnected to the second anode of the triac 862 and the other end isconnected to the other input terminal of the constant power supplycircuit 87 and the other power input terminal of the device main unit61.

The constant power supply circuit 87 is capable of outputting a currentthat has a current value equal to or higher than a current value thatthe rectifier circuit 82 can output and is enough to cause the LED 861 aof the phototriac 861 to emit light to place the triac 861 b in the onstate.

The voltage detector circuit 88 is composed of two resistors 881 and 882connected in series. One end of the series of the two resistors 881 and882 is connected to the positive output terminal of the constant powersupply circuit 87 and the other end is grounded. The connecting pointbetween one resistor 881 and the other resistor 882 is connected to theinput port terminal of the CPU 841. The CPU 841 detects the on/off stateof the triac 862 by detecting whether the voltage level output from thevoltage detector circuit 88 is high or low.

The configuration described above allows electric power from thecommercial alternating current power source 63 to be supplied to thedevice main unit 61 to cause the device main unit 61 to operate when thetriac 862 is in the on state. When the triac 862 is in the off state,power from the commercial alternating current power source 63 to thedevice main unit 61 is shut off.

Details of remote control for turning on/off the device main unit 61 bymeans of the operation directing unit 52 and the operation control unit62 of the present invention will be described below with reference toflowcharts in FIGS. 18 and 19.

According to the present embodiment, the audio device 60 can be turnedon/off by pressing the operation switch 741 on the remote control unit50 to momentarily flip it on, as described above.

The CPU 731 of the operation directing unit 52 monitors whether thepower operation switch 741 is turned on (SE1) and, if it is turned on,sends a start signal (SE2).

When the start signal is sent from the operation directing unit 52, ahigh-frequency electromotive force is induced at the antenna 81 in theoperation control unit 62 by a carrier signal of the start signal, itsenergy is rectified and smoothed by the rectifier circuit 82 intoelectric energy, and stored in the capacitor 823. This causes electricpower to be supplied to the detector section 83 and the centralprocessing section 84 in the operation control unit 62 to cause theseelectronic circuits to start operating.

When the CPU 841 of the operation control unit 62, which startsoperating, recognizes the reception of the start signal (SF1), itdetermines based on the level of a voltage outputted from the voltagedetector circuit 88 whether or not the device main unit 61 is inoperation, that is, the triac 862 is in the on state (SF2). If it isdetermined that the level of the voltage outputted from the voltagedetector circuit 88 is low and therefore no power is being supplied tothe device main unit 61, the CPU 841 places the FET 851 in the on stateto start power supply from the commercial alternating current powersource 63 to the device main unit 61 (SF3). On the other hand, if thelevel of the voltage outputted from the voltage detector circuit 88 ishigh and therefore power is being supplied to the device main unit 61,then the CPU 841 places the FET 852 in the on state to shut off powersupply from the commercial alternating current power source 63 to thedevice main unit 61 (SF4).

When the FET 851 is placed in the on state by the above-described stepSF3, current is conducted to the LED 861 a of the phototriac 861 throughthe FET 851, resistor 855, and diode 853 to cause the LED 861 a to emitlight and turn on the triac 861 b. This triggers the gate of the triac862 through the on-state triac 861 b and resistor 864 to turn on thetriac 862.

When the triac 862 is turned on, electric power is supplied to theconstant power supply circuit 87 and the device main unit 61 through thetriac 862 and to cause the device main unit 61 to start operating andcurrent is conducted to the switching operation circuit 85 and thevoltage detector circuit 88 from the constant power supply circuit 87.This causes the current to be conducted to the LED 861 a of thephototriac 861 through the resistor 856 and diode 854 from the constantpower supply circuit 87.

Thus, after the electric power stored in the capacitor 823 of therectifier circuit 82 is exhausted and the operation of the CPU 841stops, the phototriac 862 is still kept in the on state to keepsupplying power to the device main unit 61.

On the other hand, if the FET 852 is placed in the on state by theabove-described step SF4, the anode of the LED 861 a is grounded throughthe FET 852 to turn off the LED 861 a. This places the triac 861 b inthe off state. When the triac 861 b is placed in the off state, thetrigger input into the gate terminal of the triac 862 is lost to turnoff the triac 862, shutting off the power supply from the commercialalternating current power source 63 to the device main unit 61. Thus,once the triac 862 is turned off and the power supply from thecommercial alternating current power source 63 to the device main unit61 is shut off, no power is consumed in the audio device 60.

A clock circuit in the device main unit 61 for measuring time may beoperated on a rechargeable secondary battery and time of day may bedisplayed by using electric power from the secondary battery or may bedisplayed on a display only while the device main unit 61 is beingsupplied with power from the commercial alternating current power source63.

If additional output power from the rectifier circuit 82 is desirable, asolar battery may be connected in parallel with the output of therectifier circuit 82 as an auxiliary power supply. Furthermore, waveenergy of light or sound in the ambient atmosphere may be converted intoelectric energy to use as the auxiliary power supply.

If it is desirable to provide a manual power switch in the configurationshown in FIG. 17, an on switch 891 and off switch 892 may be provided asshown in FIG. 20. The on switch 891 is interposed between one inputterminal of the constant power supply circuit 87 and the triac 862 sothat the constant power supply circuit 87 is connected with the secondanode of the triac 862 (on thecommercial-alternating-current-power-source 63 side) when it isdepressed and otherwise with the first anode (on the device main unit 61side) of the triac 862. Here, it is preferable that the capacity of thecapacitor at the output of a smoothing circuit of the constant powersupply circuit 87 be set large enough to avoid a reduction in outputpower from the constant power supply circuit 87 on switching of the onswitch 891. The off switch 892 is composed of a momentary switchconnected across and in parallel with the drain and source of the FET852.

While the start signal in the fourth embodiment is composed of only theheader part of the start signal in the first embodiment, a start signalmay be used that is, composed of a header part and an information part,like the start signal in the first embodiment, so that identificationinformation can be used to select an electronic device to be poweredon/off if there are a plurality of electronic devices.

While the same start signal is used to start and end the operation of anelectronic device, that is, to power on and off the electronic device inthe fourth embodiment, a start signal similar to the one used in thefirst embodiment may be used, and in addition, a power on switch and apower off switch may be provided in the operation directing unit,switching information for specifying power on and off may be stored inthe word part of the start signal, and the operation control unit 62 maycontrol switching of the switch section 86 based on the switchinginformation. In this case, the start signal specifying power off wouldbe a shutdown signal.

A fifth embodiment of the present invention will be described below.

FIG. 21 is a block diagram of electric system circuitry of an operationdirecting unit 52B according to the fifth embodiment and FIG. 22 is ablock diagram of an electric system circuitry of an operation controlunit 62B according to the fifth embodiment. In the diagrams, the samecomponents as those in the fourth embodiment described above arerepresented by the same reference numerals and the description of whichwill be omitted. The fifth embodiment differs from the fourth embodimentin that the power on and off of three electronic devices 64A–64C can beswitching-controlled by wireless remote control from the operationdirecting unit 52B in the fifth embodiment. In addition, a remotecontrol unit 50B is provided that contains only the operation directingunit 52B in a casing and three lighting apparatuses installed in aliving room represent first through third electronic devices 64A–64C inthe fifth embodiment.

That is, the operation directing unit 52B in the fifth embodiment has aconfiguration including an operation section 75 containing three poweroperation switches 751–753, in place of the operation section 74 of theoperation directing unit 52 of the fourth embodiment.

Furthermore, a central processing section 73 identifies one of the firstthrough third power operation switches 751–753 that is turned on andsends a start signal including identification information about thecorresponding one of the first through third electronic devices 64A–64Cassociated with the first through third power operation switches751–753.

The start signal generated by the central processing section 73 iscomposed on a header part and an information part, like the firstembodiment described above, and identification information about one ofthe electronic devices 64A–64C that is to be operated is contained inthe ID part.

The operation control unit 62B in the fifth embodiment comprises,besides the configuration of the operation control unit 62 in the fourthembodiment, additional two sets of a switching operation section 85, aswitch section 86, a constant power supply circuit 87, and a voltagedetector circuit 88, that is, three sets in total. Each of the threeswitch sections 86A–86C is connected interposedly between the powersupply terminal of corresponding one of the first through thirdelectronic devices 64A–64C and a commercial alternating current powersource 63.

In the fifth embodiment, identification information about the firstthrough third electronic devices 64A–64C is pre-stored in a centralprocessing section 84 in the operation control unit 62B. The centralprocessing section 84 detects identification information contained in astart signal it received and turns on/off the switch section 86A–86C ofone of the electronic devices 64A–64C that corresponds to theidentification information.

In the fifth embodiment having the configuration described above, any ofthe first through third power operation switches 751–753 in the remotecontrol unit 50B can be pressed to momentarily turn it on to poweron/off one of the electronic devices 64A–64C corresponding to theswitch, as described above.

That is, the central processing sections 73 and 84 of the operationdirecting unit 52B and the operation control unit 62B operate asillustrated in flowcharts in FIGS. 23 and 24. The central processingsection 73 of the operation directing unit 52B monitors whether any ofthe first through third power operation switches 751–753 (SG1, SG3, andSG5) is turned on and, if the first power operation switch 751 is turnedon, sends a start signal in which the identification number of the firstelectronic device 64A is specified (SG2). If the second power operationswitch 752 is turned on, it sends a start signal in which theidentification number of the second electronic device 64B is specified(SG4). If the third power operation switch 753 is turned on, it sends astart signal in which the identification number of the third electronicdevice 64C is specified (SG6).

When any of the above-described start signals is sent from the operationdirecting unit 52B, a high-frequency electromotive force is induced atthe antenna 81 by a carrier signal of the start signal in the operationcontrol unit 62B and the energy is rectified and smoothed by therectifier circuit 82 into electric energy, which causes electric powerto be supplied to the detector section 83 and central processing section84 to cause these electronic circuits to start operating.

When the central processing section 84 of the operation control unit 62,which has started operating, recognizes the reception of a start signalfor the first electronic device (SH1), it determines based on the levelof a voltage outputted from the voltage detector circuit 88A associatedwith the first electronic device 64A whether or not the first electronicdevice 64A is in operation, that is, whether the triac 862 of the switchsection 86A associated with the first electronic device 64A is in the onstate (SH2). If the result of the determination is that the level of avoltage outputted from the voltage detector circuit 88A is low and nopower is being supplied to the first electronic device 64A, the centralprocessing section 84 places the triac 862 in the switch section 86Acorresponding to the first electronic device 64A in the on state tostart power supply from the commercial alternating current power source63 to the first electronic device 64A (SH3). If the level of the voltageoutputted from the voltage detector circuit 88A is high and power isbeing supplied to the first electronic device 64A, the centralprocessing section 84 places the triac 862 in the switch section 86Acorresponding to the first electronic device 64A in the off state toshut off power supply from the commercial alternating current powersource 63 to the first electronic device 64A (SH4).

When the central processing section 84 recognizes reception of a startsignal for the second electronic device (SH5), it determines based onthe level of a voltage outputted from the voltage detector circuit 88Bassociated with the second electronic device 64B whether or not thesecond electronic device 64B is in operation, that is, whether the triac862 in the switch section 86B associated with the second electronicdevice 64B is in the on state (SH6). If the result of the determinationis that the level of a voltage outputted from the voltage detectorcircuit 88B is low and no power is being supplied to the secondelectronic device 64B, the central processing section 84 places thetriac 862 in the switch section 86B associated with the secondelectronic device 64B in the on state to start power supply from thecommercial alternating current power source 63 to the second electronicdevice 64B (SH7) On the other hand, if the level of the voltageoutputted from the voltage detector circuit 88B is high and power isbeing supplied to the second electronic device 64B, the centralprocessing section 84 places the triac 862 in the switch section 86Bassociated with the second electronic device 64B in the off state toshut off the power from the commercial alternating current power source63 to the second electronic device 64B (SH8).

When the central processing section 84 recognizes reception of a startsignal for the third electronic device (SH9), it determines based on thelevel of a voltage outputted from the voltage detector circuit 88Cassociated with the third electronic device 64C whether or not the thirdelectronic device 64C is in operation, that is, whether or not the triac862 in the switch section 86C associated with the third electronicdevice 64C is in the on state (SH10). If the result of the determinationis that the level of a voltage outputted from the voltage detectorcircuit 88C is low and no power is being supplied to the thirdelectronic device 64C, the central processing section 84 places thetriac 862 in the switch section 86C associated with third electronicdevice 64C in the on state to start power supply from the commercialalternating current power source 63 to the third electronic device 64C(SH11). On the other hand, if the level of the voltage outputted fromthe voltage detector circuit 88C is high and power is being supplied tothe third electronic device 64C, the central processing section 84places the triac 862 in the switch section 86C associated with the thirdelectronic device 64C in the off state to shut off the power from thecommercial alternating current power source 63 to the third electronicdevice 64C (SH12).

Because no power is consumed in the first through third electronicdevices 64A–64C and the operating control unit 62B while the firstthrough third electronic devices 64A–64C are in the non-operation stateafter the triacs 862 in the switch sections 86A–86C are placed in theoff state by the above-described arrangement, the first through thirdelectronic devices 64A–64C can be powered on/off by remote control fromthe operation directing unit 52B without unnecessarily consumingelectric power.

A sixth embodiment of the present invention will be described below.

FIG. 25 is a block diagram showing electric system circuitry of anoperation directing unit according to the sixth embodiment and FIG. 26is a block diagram showing electric system circuitry of an operationcontrol unit according to the sixth embodiment. In the diagrams, thesame components as those in the fourth embodiment described above arelabeled with the same reference numerals and the description of whichwill be omitted.

While in the fourth embodiment, signal transmission between theoperation directing unit 52 and the operation control unit 62 isperformed through electromagnetic waves, signals are transmitted throughvisible light or infrared rays in the sixth embodiment.

The antenna 72 and transmitter 721 used in the fourth embodiment arereplaced with a drive circuit 723 and a light emitter 724 in theoperation directing unit 52C according to the sixth embodiment as shownin FIG. 25. The drive circuit 723 drives the light emitter 724 based ona start signal outputted from a D/A converter circuit 722 to send alight signal corresponding to the start signal. The light emitter 724 ismainly formed by a material that emits light in accordance with anelectric signal inputted into it. For example, the light emitter 724 isformed by an LED. This arrangement enables the transmission of a startsignal from the operation directing unit 52C using light.

The operation control unit 62 c according to the sixth embodimentcomprises an optical/electrical converter 91 in place of the antenna 81used in the fourth embodiment, as shown in FIG. 26. Theoptical/electrical converter 91 is mainly formed by a material thatproduces an electromotive force corresponding to the intensity of lightwhen it is applied to it. The optical/electrical converter 91 may becomposed of a phototransistor and a solar cell, for example. Theelectromotive force outputted from the optical/electrical converter 91is inputted into a rectifier circuit 82, where it is converted intooperating power for a detector section 83 and a central processingsection 84. In addition, the electromotive force outputted from theoptical/electrical converter 91 is inputted into the detector section83, where a start signal is detected.

The arrangement described above allows the start signal to betransmitted from the operation directing unit 52C to the operationcontrol unit 62C by means of light in place of electromagnetic waves. Inaddition, like the fourth embodiment, unnecessary electric powerconsumption is avoided in the sixth embodiment.

A seventh embodiment will be described below.

FIG. 27 is a block diagram showing electric system circuitry of anoperation directing unit according to the seventh embodiment and FIG. 28is a block diagram showing electric system circuitry of an operationcontrol unit according to the seventh embodiment. In the diagrams, thesame components as those in the fourth embodiment are indicated by thesame reference numerals and the description of which will be omitted.

While signal transmission between the operation directing unit 52 andthe operation control unit 62 in the fourth embodiment is performed viaelectromagnetic waves, signals are transmitted via sound waves such asaudible sound or ultrasonic waves in the seventh embodiment.

The antenna 71 and the transmitter 721 used in the fourth embodiment arereplaced with a drive circuit 725 and an ultrasonic transmitter 726 inthe operation directing unit 52D according to the seventh embodiment asshown in FIG. 27. The drive circuit 725 drives the ultrasonictransmitter 726 based on a reply signal outputted from a D/A convertercircuit 722 to send an ultrasonic signal corresponding to a startsignal. The ultrasonic transmitter 726 is mainly formed by a materialthat oscillates in accordance with an electric signal inputted andgenerates an ultrasonic wave by this oscillation. The ultrasonictransmitter 726 may be formed by a piezoelectric element, for example.The above-described arrangement enables the transmission of a startsignal from the operation directing unit 52D via an ultrasonic wave.

The operation control unit 62D according to the seventh embodimentcomprises an ultrasonic receiver 92 in place of the antenna 81 used inthe fourth embodiment, as shown in FIG. 28. The ultrasonic receiver 92is mainly formed by a material that oscillates in resonance with anultrasonic signal applied to it and produces an electromotive force. Theultrasonic receiver 92 may be formed by a piezoelectric element, forexample. An electromotive force outputted from the ultrasonic receiver92 is inputted into a rectifier circuit 82, where it is converted intoan operating power for a detector section 83 and a central processingsection 84. In addition, the electromotive force outputted from theultrasonic receiver 92 is inputted into the detector section 83, where astart signal is detected.

The arrangement described above enables transmission of the start signalfrom the operation directing unit 52D to the operation control unit 62Dby using a sound wave in place of an electromagnetic wave. In addition,like the fourth embodiment, unnecessary electric power consumption isavoided in the seventh embodiment.

According to an electronic device starter of the present invention, asdescribed with respect to the fourth to seventh embodiments by way ofexample, energy of a start signal sent from an operation directing unit52 provides electric energy for operating an operation control unit 62,the operation control unit 62 places a switch section 86 in the on statebased on the start signal, and electric power is supplied from acommercial electric power source 63 to the device main unit 61 throughthe switch section 86, therefore no electric power is consumed in thedevice main unit 61 and the operation control unit 62 while the devicemain unit 61 is in the non-operation state after the switch section 86is placed in the off state. Thus, operation of the device main unit 61can be started by remote control from the operation directing unit 52without unnecessarily consuming electric power.

The first to seventh embodiments described above are only a few specificexamples of the present invention and the present invention is notlimited by those specific configurations.

The present invention can be implemented in various other forms withoutdeparting from the spirit and main features of the present invention.Therefore, the embodiments described above are only illustrative inevery respect and should not be construed as limitative. The scope ofthe present invention is set forth in the Claims and not restrained bythe Specification. Furthermore, any variations and modifications withinthe scope of equivalents of the Claims fall within the scope of thepresent invention.

1. An electronic device starter for causing an electronic device tostart operating wirelessly from a position remote from said electronicdevice, characterized in that said device starter comprises: anoperation directing unit; and an operation control unit provided in saidelectronic device, and said operation directing unit comprises: startsignal sending means for wirelessly sending a start signal for directingsaid electronic device to start operating, and said operation controlunit comprises: receiving means for receiving a wireless signal sentfrom said operation directing unit; detection means for detecting saidstart signal from among wireless signals received by said receivingmeans; energy conversion means for converting a wireless signal receivedby said receiving means into electric energy for operating saidoperation control unit; a capacitor for charging said electric energy tosupply to said operation control unit; switch means interposed on apower supply line used for supplying operating power to said electronicdevice for turning on/off power supply to said electronic device; andswitch control means for changing said switch means from an off state toan on state when said start signal is detected by said detection meansand for maintaining said switch means to the on state with the use ofelectric energy charged by said capacitor during predetermined timewhich is not received the wireless signal by said receiving means afterthe start signal is detected by said detection means and said switchmeans is changed to the on state.
 2. The electronic device starteraccording to claim 1, characterized in that said operation directingunit comprises means for sending said start signal at predetermined timeintervals in a period from operation start time to operation stop timeof said operation directing unit; the switch control means of saidoperation control unit comprises means for placing said switch means inthe on state only while electric power is being supplied from saidcapacitor; and the transmission time intervals of said start signal areset shorter than a time period in which said energy conversion means cansupply by reception of one start signal an amount of electric energythat can operate said operation control unit for a predetermined time.3. The electronic device starter according to claim 1, characterized inthat said start signal includes operation-start-instruction informationfor instructing said electronic device to start operating andidentification information for identifying an electronic device to bestarted; said operation control unit comprises means for storingidentification information assigned to an electronic device to becontrolled by said operation control unit; and said switch control meanscomprises means for placing said switch means in the on state if saidstored identification information matches the identification informationincluded in said start signal.
 4. The electronic device starteraccording to claim 3, characterized in that said operation control unitstores a plurality of different pieces of identification information andcontrols operation of a plurality of electronic devices associated withsaid plurality of pieces of identification information.
 5. Theelectronic device starter according to claim 1, characterized in thatsaid energy conversion means has auxiliary energy means for convertingat least one wave selected from a group consisting of an electromagneticwave, a sound wave, an ultrasonic wave, and light in ambient atmosphereinto electric energy and supplying the electric energy to said operationcontrol unit.
 6. The electronic device starter according to claim 1,characterized in that the wireless signal sent from said operationdirecting unit to said operation control unit is an electromagneticwave.
 7. The electronic device starter according to claim 1,characterized in that the wireless signal sent from said operationdirecting unit to said operation control unit is an ultrasonic wave. 8.The electronic device starter according to claim 1, characterized inthat the wireless signal sent from said operation directing unit to saidoperation control unit is light.
 9. A vehicle tire monitoring systemhaving a plurality of detectors, each of which is provided at each tireand includes a sensor unit operating on electric power supplied from abattery and communication means for wirelessly sending tire conditionsdetected by said sensor unit as detection information; and a monitorunit installed in the vicinity of the driver's seat of a vehicle forreceiving and displaying the detection information sent from saiddetectors, characterized in that said monitor unit comprises startsignal sending means for wirelessly sending a start signal for directingsaid detectors to start operating; said detectors each comprisingoperation control means; said operation control means comprises:receiving means for receiving the start signal sent from said monitorunit; detection means for detecting said start signal from among signalsreceived by said receiving means; energy conversion means for convertinga signal received by said receiving means into electric energy foroperating said operation control means; a capacitor for charging saidelectric energy to supply to said operation control unit; switch meansinterposed on a power supply line supplying operating power from saidbattery to said sensor unit for turning on/off electric power supply tosaid sensor unit; and switch control means for changing said switchmeans from an off state to an on state when said start signal isdetected by said detection means and for maintaining said switch meansto the on state with the use of electric energy charged by saidcapacitor during predetermined time which is not received the wirelesssignal by said receiving means after the start signal is detected bysaid detection means and said switch means is changed to the on state.10. The vehicle tire monitoring system according to claim 9,characterized in that said system further comprises means for supplyingelectric power to said monitor unit to operate said monitor unit onlywhile an ignition key of said vehicle is in an on state; the switchcontrol means of said operation control means comprises means forplacing said switch means in the on state only while electric power isbeing supplied from said energy conversion means; and said monitor unitcomprises means for sending said start signal at predetermined timeintervals in a time period from operation start time to operation stoptime of said monitor unit; and the transmission time intervals of saidstart signal are set shorter than a time period in which said energyconversion means can supply by reception of one start signal an amountof electric energy that can operate said operation control unit for apredetermined time.
 11. The vehicle tire monitoring system according toclaim 9, characterized in that the wireless signal sent from saidmonitor unit to said operation control means is an electromagnetic wave.12. The vehicle tire monitoring system according to claim 9,characterized in that said start signal is set as a request to senddetection information and said detector comprises means for performing aprocess for transmitting the detection information when said startsignal is received by said receiving means.
 13. The vehicle tiremonitoring system according to claim 9, characterized in that saidcommunication means operates on electric energy outputted from saidenergy conversion means.